Anyway... As part of my iPlayer custom podcast solution I needed to be able to connect to my Pi externally over the internet.
Sign up for a host with no-ip.com
My ISP assigns IP addresses dynamically (pretty typical but not very useful for accessing from the internet), so I setup a free account with www.no-ip.com who offer a free dynamic dns service whereby they provide you with a URL (e.g. myhost.no-ip.org) and they redirect internet traffic from that URL to your IP address.
You can either login to no-ip.com and update your ip address manually, as and when it changes (not practical!), or no-ip provide client software which will run in the background on your Pi and periodically update your no-ip host with your IP address.
Note - Its important you create yourself an account and add a host on no-ip before installing the client as you will need your account details as part of the install.
Install no-ip client
(most of this detail is taken from http://www.no-ip.com/support/guides/update_clients/setting_up_linux_update_client.html but there are a few discrepancies)
Create a directory for the client software
Download the client software
Extract the archive
Navigate to the archive directory
Note - use 'ls' to check the directory name create when the archive was extracted, it was noip-2.1.9-1 when I installed the client.
Compile and install
The client was compiled and installed on the Raspberry Pi, using the following commands:
During the install I was asked to proide my login, password and a refresh interval.
Run the client
The client is run using the following command:
The client runs continuously until shutdown or the Raspberry Pi is shutdown, if you want to set up your Pi so the no-ip client is started at boot, check out this blog which describes how to configure the application to start at boot.
I then had to configure my broadband router to forward the specific port I wanted my Pi to service (e.g. port 80 for www) to the internal IP address of my Raspberry Pi, see portforward.com for more information about port forwarding guides and info; you may find setting up port forwarding simpler if your raspberry Pi has a static IP address, see this post on how to set a static IP address.